It has become highly desirable to bury electrical transmission cables underground. Assemblies for such underground applications, for example, connectors wherein a tap conductor is joined to a run conductor, must be specifically designed with this underground use in view. Where direct burial has taken place, the connection of electrical conductors is made and left frequently without the benefit of a protective enclosure in the ground. Therefore, the connector must be moisture proof and proper sealing must be provided. This condition is aggravated by the fact that in underground insulations there is a tremendous buildup of pressure due to variations of moisture in the air and the connector must be designed with this factor being recognized.
Various solutions have been derived to maintain the water tight seals necessary between the components utilized in connecting the tap conductor to the underground run conductor. Examples are apparent in U.S. Pat. No. 3,579,173 and U.S. Pat. No. 3,848,956.
The connectors must be easily applied without the use of special tools and provide for installation while the cable is "live", provide good mechanical and electrical connections with appropriate moisture seals, have long life underground and be capable of easy disconnect of the tap connector with a minimum amount of repairs for the run conductor required. Additionally, there must be no need for cutting the main cable during installation, of "skinning" either the main run conductor cable or tap conductor, and there must be no installation damage to the line or cable resulting from the application of the connector.
An additional problem which is now recognized and which should be avoided is the application of undue stress to the insulation of the run conductor when the connection is made causing the insulation to crack or deteriorate over a period of time which would, of course, cause leakage and undesirable damage. Furthermore, the connection should be of the type whereby minimum distortion of the run conductor results when the connection is made. This applies to both the exterior insulation material and the interior conductor wires. Damage to the interior wires should be maintained at a minimum and if possible the wire should not be disturbed at all.